Installing a new door knob handle on a hollow door is really no different than a solid door. For the most part, a door is a door.
The cut-out for the knob is the same size and so it will go into the hole for it, regardless of whether or not the door is a hollow core door or solid.
Installing the handle is a five minute process.
The handle will come in two halves that go on either side of the door. Obviously, make sure the lock mechanism is on the correct side of the door. On any locking handle, the screws will be on the interior side of the door and the handle side that locks will be on the exterior side of the door. Just make sure you have the correct side of the handle on the right sides of the door.
Install the latch button assembly into the edge of the door. This gets secured to the door with two wood screws. Push the two halves of the knob together and match up the holes. The two halves will mate with the latch assembly so that when everything is together, the door knob will engage the latch and move it in-and-out. Install the screws from the interior side of the door into the exterior side of the handle and tighten them until snug.